1. Field of the Invention
This invention relates to portable fluid blowers and, more particularly, to blowers that have a discharge end that can be controllably positioned by a user.
2. Background Art
Portable blowers have been used, particularly in the landscaping area, for decades. Common to these designs is the ability of a user to control placement of the fluid discharge end so as to select both discharge flow direction and location.
The portable configurations vary widely. As one example, a portable blower may be configured as shown in FIG. 1 of U.S. Pat. No. 5,926,910, wherein a housing containing the propulsion components is directly held by a user. A discharge conduit is in fixed relationship to the housing so that the user is required to reorient the entire apparatus as a unit to control air discharge.
In an alternative form, as shown in FIG. 7 of U.S. Pat. No. 6,077,033, a flexible conduit is provided to communicate air from a propulsion unit to an opening at the discharge end of a nozzle. The user exploits the flexibility of the conduit to control direction and location of the air discharge.
Common to virtually all designs is the provision of a nozzle with a discharge opening and a rim that extends around the opening and bounds a shape and area determinative of discharge volume and flow velocity. These units are commonly designed with the capacity of the propulsion unit matched to the conduit and discharge opening to generate air flow volume and velocity that are considered to be optimal. So long as the discharge opening, as determined by the rim shape, remains constant in configuration, the unit will have consistent operating characteristics.
Commonly, the rim defining the discharge opening area is integral with a length of conduit or a nozzle fitting attached appropriately to a conduit. Most commonly, the conduits and all associated fittings communicating air between the propulsion unit and the discharge opening, including the rim at the discharge end, are made from plastic material. This material selection is made primarily for weight minimization, particularly since most units are designed to be held by a user in an elevated position during use. Available plastics also generally have good durability.
However, a typical blower used by a landscaping crew may, over an extended period, experience significant wear. One area of concern is with the rim at the discharge end of the conduit or nozzle fitting. The exposed region of the rim may be repeatedly impacted against hard surfaces or dragged on those surfaces, as a result of which there may be progressive wear that changes the configuration of the rim and thereby potentially the effective area and/or shape of the discharge opening that it bounds. Whereas, when new, the capacity of the propulsion unit and the area and shape of the discharge opening are closely matched to optimize performance, over time this relationship may be altered as a result of which air discharge patterns, velocity, and/or volume may be detrimentally affected.
For the most part, changes in operating characteristics attributable to a reconfiguration of the rim at the discharge end of the conduit or nozzle fitting, due to wear, may be gradual. As a result, the user may not even detect any performance compromise and may eventually attribute less than optimal performance to the original unit design. This may reflect poorly on the manufacturer when, in fact, the compromised performance due to regular anticipated wear may be inevitable with all of these types of blowers.
As a practical matter, those using blowers of this type on a daily basis are unlikely to be monitoring the condition of the rim at the discharge end. Even if regular monitoring is undertaken, replacement of part or all of the assembly communicating between the propulsion unit and the discharge end may be an inconvenience and represent a significant expense. This is aggravated by the fact that the rim at the discharge end may often be integrated with other conduit and fitting components so that the replacement part(s) may be somewhat expensive.
The reality is that users of portable blowers, particularly in the landscape industry, are not likely to regularly maintain the air communication components between the propulsion unit and the discharge end. Rather, they eventually contend with compromised unit performance which may translate into additional time needed to perform routine landscaping tasks or performance of tasks in an ineffective manner.
The industry continues to seek out improvements in this type of equipment that will contribute to greater product life without significantly increasing either the weight or cost of such equipment.